-- Entity Declaration

ENTITY buf IS
  PORT (
  i : in BIT;	-- i
  q : out BIT;	-- q
  vdd : in BIT;	-- vdd
  vss : in BIT	-- vss
  );
end buf;


-- Architecture Declaration

ARCHITECTURE data_flow OF buf IS

signal nq:bit;

BEGIN
  
nq <= not (i);
q  <= not (nq);

end data_flow;